Field of Invention
This disclosure relates to combining two or more images to produce a fused image.
Description of Related Technology
Some image processing devices, such as smartphones or tablet computers, are able to capture images of objects (e.g., a person, place, location, etc.). Such image processing devices may also process the images to feature desirable aspects of the images and to mitigate undesirable aspects of the images. For example, an image processing device may perform post-processing operations on an image to reduce red-eye, to improve color balance, and/or to apply different photographic filters to the image to make the image more visually appealing to the user.
Multi-image fusion is a post-processing technique in which desirable aspects of separate images of the same scene are blended together, thereby increasing the overall visual quality of the resulting or “fused” image. Some multi-image-fusion techniques allow image processing devices to generate a fused image that incorporates exposure information from multiple images (sometimes referred to as multi-exposure fusion or high-dynamic-range imaging). In multi-exposure fusion, multiple images of the same scene are combined to achieve a high dynamic range. For example, multi-exposure fusion may blend images that feature a light source (e.g., the sun) in the background and a non-light source (e.g., a person) in the foreground.
Other multi-image fusion techniques may be used to generate a fused image that incorporates focus characteristics from multiple images (sometimes referred to as “multi-focus fusion”). In multi-focus fusion, multiple images of the same scene are captured, and each image is focused on a different object in the scene. For example, one image may have the background object in focus, and a second image may have the foreground object in focus. These images are fused/blended together in order to generate a consolidate image in which each object is in focus.
Another multi-image fusion technique is used to generate a fused image that incorporates different illumination characteristics from multiple images (sometimes referred to as “multi-illuminant fusion”). In multi-illuminant fusion, multiple images of the same scene are combined to achieve compensation for each illuminated object in the scene. For example multi-illuminant fusion may blend images that feature objects illuminated by a natural day light and objects illuminated by indoor lights such as cool-white fluorescent light or tungsten-based light. However, each of these techniques alone provides a sub-optimal solution, and combinations of such techniques can require enormous processing power which may not be available or desired.